title: Association of Biomarkers for Inflammation, Endothelial Dysfunction and Oxidative Stress with Cognitive Impairment. The Epidemiology of Hearing Loss Study (EHLS).
abstract: BACKGROUND
  Individual biomarkers of inflammation, endothelial dysfunction and oxidative stress have been associated with cognitive impairment. This study explored whether a combination of biomarkers could prospectively identify those who developed cognitive decline.
  
  
  METHODS
  Biomarkers were obtained during the baseline examination of the Beaver Dam Eye Study (1988-90), and cognitive status was assessed during the 5-year follow-up examination of the Epidemiology of Hearing Loss Study (1998-2000). Cognitive impairment was defined as a score of < 24 points on the Mini-Mental State Examination or self- or proxy report of Alzheimer Disease or dementia. Among those with cognitive data, interleukin-6, isoprostanes, protein carbonyl, soluble inter-cellular adhesion molecule-1 and vascular cell adhesion molecule-1 were available for 950 participants and 2,336 had high sensitivity C-reactive protein.
  
  
  RESULTS
  Biomarkers of inflammation and endothelial dysfunction were not associated with cognitive impairment. There was a weak inverse association between higher levels of protein carbonyl content and cognitive impairment (OR, 0.8 per quartile of protein carbonyl content, p=0.045 unadjusted for multiple comparisons). This was not significant on multiple testing and may have been a chance finding.
  
  
  CONCLUSIONS
  We found that many markers of inflammation and endothelial dysfunction were not associated with cognitive impairment. An inverse association with carbonyl protein, a marker of oxidative stress needs further confirmation.
authors.affiliation: Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI USA.
authors.forename: Chidi N
authors.initials: CN
authors.lastname: Obasi
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Cruickshanks
authors.forename: David M
authors.initials: DM
authors.lastname: Nondahl
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Nieto
authors.forename: Anoop
authors.initials: A
authors.lastname: Shankar
authors.forename: Mary E
authors.initials: ME
authors.lastname: Fischer
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Tsai
authors.forename: Rick
authors.initials: R
authors.lastname: Chappell
keywords: biomarkers; cognitive impairment; inflammation; oxidative stress